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Creatinine, Plasma / Serum
|Test Update Information||Effective November 16, 2016, the UCSF Clinical Labs switched to an enzymatic creatinine assay. Please note updated reference ranges.
Since December 1, 2014, the eGFR has been calculated using the CKD-EPI (2009) equation
|Performed by||Parnassus, Mission Bay & Mt. Zion Chemistry|
|In House Availability||Test available 24 hours per day 7 days per week|
|Method||Enzymatic assay on Beckman DXC 600/800 analyzers. Calibration traceable to isotope dilution mass spec (IDMS) standardization.
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|Container type||Light green top preferred, Gold top acceptable|
|Amount to Collect||1 mL blood Click here for Microdetermination info|
|Sample type||Plasma or serum|
|Preferred volume||0.5 mL plasma or serum|
|Min. Volume||0.2 mL plasma or serum
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|Units||Creatinine: mg/dL, eGFR in mL/min/1.73 m2|
|Normal range|| Creatinine:
1. Pediatric reference ranges adopted from "CLSI-based transference of the CALIPER database of pediatric reference intervals to Beckman Coulter DxC biochemical assays" Clinical Biochemistry 48 (2015) 870–880
2. Normal range for adults was adopted from vendor Chemistry Information Sheet and verified by running 53 female and 44 male lab volunteers at UCSF Clinical Labs.
|Synonyms||GFR; eGFR; glomerular filtration rate|
|Stability||Room temperature 8 hours, refrigerated 2 days, frozen at -20C 1 week|
|Turn around times||STAT 1 hour, Routine 4 hours|
|Additional information||To convert mg/dL to µmol/L (SI units) multiply by 88.4.
Estimated GFR (eGFR) is reported with serum creatinine results in adults and is determined using the CKD-EPI equation (creatinine results traceable to isotope dilution mass spec IDMS calibration). Results greater than 120 mL/min/1.73 meters squared body surface area are displayed as > 120 mL/min and are not reported as an exact number. Note that the estimated GFR result is not reliable in certain groups including severely ill patients. Estimates of GFR with the CKD-EPI equation like other equations may also be less accurate in specific ethnic groups (eg, Asians in the United States), pregnant women, and those with unusual muscle mass, body habitus, and weight (eg, morbid obesity, amputees). Reference: Assessment of Kidney Function. WWW.UpToDate.com
GFR = 141 x min (Scr /κ, 1)α x max(Scr /κ, 1)-1.209 x 0.993Age x 1.018 [if female] x .159 [if African-American]
- Scr is serum creatinine in mg/dL,
- κ is 0.7 for females and 0.9 for males,
- α is -0.329 for females and -0.411 for males,
- min indicates the minimum of Scr /κ or 1, and
- max indicates the maximum of Scr /κ or 1.
According to the National Kidney Disease Education Program, the best equation for estimating glomerular filtration rate (GFR) from serum creatinine in children is the Bedside Isotope Dilution Mass Spectrometry (IDMS)-traceable Schwartz equation
Bedside IDMS-traceable Schwartz Equation for Children
GFR (mL/min/1.73 m2) = (0.41 x Height in cm) / Creatinine in mg/dL)
|Last Updated||11/16/2016 8:22:37 AM|